Pipe pulling machine

ABSTRACT

A machine for installing flexible pipe underground for use in lawn sprinkling systems and the like, said machine consisting of carriage powered for movement over the ground surface, a generally vertical blade mounted on the carriage and adapted to project into the ground, a digging &#39;&#39;&#39;&#39;mole&#39;&#39;&#39;&#39; carried at the lower end of the blade and having a forwardly projecting spade point, mechanism mounted on the carriage and powered to impart to the blade and mole an orbital motion in a vertical plane aligned with the direction of movement of the carriage, whereby said mole digs a tunnel in the ground, a connector for joining a pipe to the rearward end of the mole, whereby the pipe is pulled into the tunnel, and apparatus for ejecting water from the mole, whereby the digging action of the mole is facilitated and the passage of the pipe through the tunnel is lubricated. The machine may also be used for the subterranean installation of flexible cables or other conduits.

United States Patent 1191 Stewart et al.

[ Sept. 25, 1973 PIPE PULLING MACHINE 3,611,596 10/1971 Bright 61 726 x [76] Inventors: Edward T. Stewart, 107 Plaza Ter., P E J b Sh Dodge City, Kans. 67801; Jerald W. Z f izi gz s g aplro Bishop, 1506 Highway 56, Dodge 0 57 ABSTRACT [22] Flled: 9, 1971 A machine for installing flexible pipe underground for [21] APPL No; 169,995 use in lawn sprinkling systems and the like, said machine consisting of carriage powered for movement over the ground surface, a generally vertical blade U-s. Clmounted on the carriage and adapted to project into 172/40 the ground, a digging mole carried at the lower end [51] f Aolb 3/64 Aolb "/00, F161 1/00 of the blade and having a forwardly projecting spade Fleld of Search n 72-6, 72.7, point, mechanism mounted on the carriage and pow 61/72-1; 37/193; 172/40; 74/86 ered to impart to the blade and mole an orbital motion in a vertical plane aligned with the direction of move- References Cited ment of the carriage, whereby said mole digs a tunnel UNITED STATES PATENTS I in the ground, a connector for joining a pipe to the 3,713,300 1/1973 Ward 61/726 rearward end of the mole, whereby the P is Pulled 734,615 7/1903 Rober 61/71 X into the tunnel, and apparatus for ejecting water from 3,214,920 11/1965 Jacobs 61/72.? X the mole, whereby the digging action of the mole is fa- 3,326,009 1967 G g e t 61/72-6 cilitated and the passage of the pipe through the tunnel 1,112,894 10/1914 Clark 61/72. X is lubricated. The machine may also be used for the 32951333 H1967 K'noren 61/724, subterranean installation of flexible cables or other 1,765,185 6/1930 Umbarger.... 61/72.? X conduits 3,589,l35 6/l97l, Ede 6l/72.7 1,904,666 4/1933 Sack 61/72.? 6 Claims, 12 Drawing Figures M2 //0 w u;

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: 7-. zxxxgy PIPE WILLING MAGIIINE This invention relates to new and useful improvements in pipe pulling machines, and has particular reference to a machine operable to install flexible plastic water pipe or the like in underground locations for use in lawn sprinkling systems and the like, or in any other application wherein subterranean installation of such pipe or the like is desired.

The machine is of a type including a carriage powered for movement over the ground surface, and carrying a generally vertical blade extendable downwardly therefrom to project into the ground to the desired depth, with a digging element at the lower end of the blade operable to open a tunnel in the ground. The pipe is attached to the digging element and is pulled into the tunnel by forward movement of the carriage. The blade may be very narrow transversely to its width, and therefore causes only minimal and easily repaired distrubance of the ground surface. Pipe pulling machines of this general type have been previously proposed, but all such prior devices within our knowledge have had the serious shortcoming of requiring great power for their operation, especially where the ground itself is very hard and firm, or when pulling long lengths of pipe.

Accordingly, the principal object of the present invention is the provision of a pipe pulling machine of the general character described having special provisions whereby the operating power requirement thereof is reduced to a small proportion of that previously required. Generally, this object is accomplished by mechanism imparting to the blade and digging element an orbital movement in a vertical plane aligned with the direction of carriage travel, so that the digging element reciprocates rapidly both horizontally and vertically, and shaping the digging element to take advantage of this movement to produce an efficient digging action requiring very little power as compared to a device wherein the digging element is pushed through the ground with a steady,'uni-directional movement.

Another object is the provision of a pipe pulling machine of the character described including means for ejecting water from the digging element. This moisture softens the earth, further facilitating and easing the operation of the digging element, tends to compact the walls of the tunnel formed by the digging element so that said tunnel remains open after passage of the digging element and lubricates the passage of the pipe through the tunnel.

Other objects are simplicity and economy of construction, efficiency and dependability of operation, and ready adjustability to accommodate variable soil conditions.

With these objects in view as well as other objects which will appear in the course of the specification, reference will be had to the accompanying drawing, wherein:

FIG. 1 is a side elevational view of a pipe pulling machine embodying the present invention, shown in operating position,

FIG. 2 is a top plan view of the machine as shown in FIG. 1,

FIG. 3 is an inverted plan view of the machine as shown in FIG. 1,

FIG. 4 is an enlarged, fragmentary sectional view taken on line IVIV of FIG. 2,

FIG. 5 is a fragmentary sectional view taken on line V-V of FIG. 4, with parts left in elevation and partially broken away,

FIG. 6 is a fragmentary sectional view taken on line Vl-VI of FIG. 4,

FIG. 7 is a sectional'view taken on line VIIVII of FIG. 4,

FIG. 8 is a fragmentary sectional view taken on line VIII-VIII of FIG. 4,

FIG. 9 is a fragmentary sectional view taken on line IX-IX of FIG. 4,

FIG. 10 is an enlarged, fragmentary sectional view taken on line X-X of FIG. 4,

FIG. 11 is a fragmentary sectional view taken on line XIXI of FIG. It and FIG. 12 is a schematic diagram of the power and control system of the machine.

Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies generally to the carriage of the machine, said carriage including a generally horizontal heavy sheet metal platform 4 supported for movement over the ground-surface 6 by a pair of caterpillar tracks 8 disposed respectively at opposite sides thereof. Said tracks of course comprise endless loops, the forward ends of said loops being trained about sprockets I0 affixed respectively on the opposite ends of a shaft I2 extending transversely beneath platform 4 and journalled in bearings 14 afiixed to said platform, and the rearward ends of said loops being trained about sprockets 16 affixed respectively on the opposite ends of a shaft 18 extending transversely beneath platform 4 and jouranlled in bearings 20 afiixed to said platform. A hydraulic motor 22 (see FIGS. 3 and I2) is mounted on the lower side of platform 4, and a sprocket 24 mounted on the output shaft 26 of said motor is operatively connected by sprocket chain 28 with a sprocket 30 fixed on shaft 12. Another sprocket 32 fixed on shaft 12 is operatively connected by sprocket chain 34 with a sprocket 36 fixed on shaft I8. Thus operation of hydraulic motor 22 propels carriage 2 over ground surface 6.

Referring principally to FIG. 12, it will be seen that hydraulic motor 22 is furnished with hydrualic fluid by a pair of hoses 38 and 441 from a control valve 42, which in turn receives fluid through hose 44 from a hydrualic pump 46 driven by an internal combustion engine 48 or other prime mover mounted on platform 4. Pump 46 draws fluid from a reservoir 50 through a conduit 52, and fluid is returned to said reservoir from control valve 42 through a return conduit 54. Motor 22 is reversible, and valve 42 is provided with a manually operable control handle 56 by means of which it may be set to operate said motor in either direction, whereby to drive the carriage either forwardly or rearwardly as desired, at continuously adjustable speeds.

'To prevent the carriage from vibrating or bouncing vertically, under the reactive forces of the digging element to be described, a transversely extending cross bar 58 is affixed to the top of platform 4 and projects outwardly at both sides of said platform, and a heavy weight 60 is affixed to each end of said cross bar. Also, assisting in this function, in that they prevent vertical oscillation of caterpillar tracks 8 between their forward and rearward drive sprockets, are a pair of heavy bars or rails 62 of wood or other suitable material, disposed respectively within the loops of said tracks, and rigidly secured to carriage 2 by brackets 64. These rails are disposed in close proximity to the lower or groundengaging reaches of said tracks, intermediate the front sprockets l and rear sprockets 16 of said tracks, and strongly resist upward movement of said tracks. Carriage 2 is guided, as it is propelled over the ground, by a handlebar 66 which, it will be seen in FIGS. 1-3, is attached to the forward end of carriage 2, said carriage in normal usage moving forwardly in the direction of arrow 68 in FIG. 1. The carriage is steered by exerting manual force on the handlebar laterally of the carriage, or, if desired, the two tracks 8 could be provided with independently controlled drive trains for this purpose.

The digging apparatus is carried at the rearward end of carriage 2, and is best shown in FIGS. 4-11. As best shown in FIGS. 2 and 3, the rearward end portion of platform 4 is notched as indicated at 70, and a horizontal transverse cross bar 72 is fixed to said platform to extend across the rearward end of said notch. A link 74 is pivoted at its upper end, as at 76, to the midpoint of said cross bar, on a horizontal transverse axis, and is pivoted at its lower end, as at 78, to a block 80 which is fixed by bolt 82 between the arms of a double link 84 which extends forwardly beneath platform 4. Bolt 82 is engaged in slots 86 formed longitudinally in the arms of link 84, whereby block 80 may be adjusted forwardly or rearwardly relative to said link by loosening said bolt. The forward end of link 84 is engaged rotatably on an eccentric pin 88 carried by a drive shaft 90. Said drive shaft is horizontal and extends transversely of the carriage, being journalled in bearings 92 and 94 mounted on said carriage. Thus when shaft 90 is rotated, eccentric pin 88 imparts an orbital movement to the forward end of link 84.

Shaft 90 is rotated by a sprocket 96 affixed thereto, said sprocket being operatively connected by sprocket chain 98 to a sprocket 100 (see FIG. 12) driven by engine 48 through a variable speed transmission 102. Engine 48, hydraulic pump 46, reservoir 50 and transmission 102 comprise a power package enclosed by dotted line box 104 in FIG. 12, and may be mounted on the top surface of platform 4, as indicated in FIGS. 1 and 2.

A rigid upstanding post 106 is affixed rigidly to platform 4 at the forward end of notch 70, and midway of the width of said platform. A double link 108 is pivoted to the upper end of said post, as by bolt 110, and extends generally horizontally rearwardly from said pivot. Bolt 1 engages in longitudinal slots 112 formed in the arms of said link, whereby said link may be adjusted forwardly and rearwardly by loosening said bolt. A generally vertical tubular slide 114 extends between the rearward end of link 108 and an intemediate point of link 84, said slide being of rectangular cross-sectional contour and extending between the arms of said links. Said slide is pivoted at its upper end to link 108, as at 116, and at its lower end to link 84 as at 118. Mounted for longitudinal sliding movement in slide 114 is a generally vertical blade 120 constituting a flat plate with its minor axis transverse to the carriage. Said blade extends above slide 114, and is affixed rigidly by bracket 122 to the upper end of a piston rod 124 parallel with said blade. A piston 126 affixed to the lower end of said piston rod (see FIG. 5) is operable in a hydraulic cylinder 128 which is affixed rigidly to slide 1 14 by brackets 130. Hydraulic fluid may be supplied to the upper end of cylinder 128 by hose 132, whereby blade 120 is lowered, or to the lower end of said cylinder by hose 134,

whereby said blade is raised. Bracket 122 may be secured by bolt 136 in any of a series of longitudinally spaced apart holes 138 formed therefor in the blade. Referring to FIG. 12, it will be seen that hoses 132 and 134 are supplied with hydraulic fluid from a control valve 140 also connected with the delivery and return conduits 44 and 54 of hydraulic pump 46, and having a manual control handle 142 by means of which the system may be set to raise or lower blade 120 at any desired rate.

Blade 120 also projects at all times beneath slide 1 14, and by operation of cylinder 128 the lower end of said blade may be either elevated well above ground level 6, or lowered to project beneath the ground level to the depth at which it is desired to lay the flexible water pipe 144, or other flexible cable or conduit to be pulled. The forward edge of the lower portion of the blade is sharpened, as indicated at 146, to facilitate the forward movement of said blade through the ground.

Affixed to the lower end of blade 120 is a digging element 148, best shown in FIGS. 4, 10, and 11. Preferably, as shown, said digging element, or mole" is cylindrical in form with its axis at right angles to the blade and extending fore and aft of carriage 2 with its forward end extending forwardly of blade edge 146 and cut off at an angle to form a digging surface 150 which faces upwardly and forwardly. Said mole is slotted along its top side to receive the lower end of blade 120 therein, the blade and mole being secured in assembly by bolts 152. This assembly permits interchange of said mole for other moles having different diameters, the mole diameter preferably being somewhat larger than that of the pipe 144 to be pulled. Threaded axially in the rearward end of the mole is a screw eye 154 in which is engaged a snap fastener 156. A short length of chain 158 (see FIG. 4) is engaged at its forward end in said snap fastener, and a pipe gripper 160 is attached to the rearward end of said chain. Said pipe gripper is of a type common and well known in the art, consisting of a tube of loosely braided steel cables, open at its rearward end, commonly known as japanese handcuffs." It expands in diameter when axially compressed, whereby to admit the forward end of pipe 144 freely therein, but contracts in diameter when extended in length, thereby gripping said pipe firmly. Therefore, so long as it grips the pipe at all when unstressed longitudinally, its grip on the pipe will increase generally proportionately to the pulling force exerted thereby on the pipe by forward movement of carriage 2.

Mole 148 has a bore 162 formed transversely therethrough and opening at both sides thereof. A bore 164 communicating with bore 162 intemediate its ends opens through the rearward end of the mole, and a small tube 166 is fitted tightly in the rearward end of bore 164. Tube 166 extends upwardly behind and in parallel relation to blade 120, and lies in the plane of said blade, extending upwardly to a point always above the lower end of slide 114, being attached at its upper end to a flexible hose 168. Tube 166 is welded or otherwise affixed at its lower end to blade 120, as indicated at 170 in FIGS. 4 and 11, and is reinforced by a stiffener bar 172 welded or otherwise affixed thereto, and extending parallel to blade 120 therebehind and lying in the plane of said blade. Said tube and stiffener bar extend upwardly for vertical sliding movement in a tubular keeper 174 affixed to slide 114 at its lower end. Hose 168 is supplied with water from a water valve 176 (see FIG. 12), to which water is in turn furnished under pressure by a water hose 178 which may be a garden hose trailing from the machine. Hydraulic control valves 42 and 140, and water valve 176, constitute a control group as indicated by the dotted line box 180 in FIG. 12, and are preferably mounted on or directly adjacent handlebar 66, so as to be conveniently accessible to the operator.

In operation, carriage 2 is first positioned facing forwardly along the line it is desired to pull the pipe, at the starting end of said line, with piston rod 124 extended to elevate mole 148 above the ground level 6, and the end of pipe 144 inserted into gripper 160 as already de scribed. Then hydraulic motor 22 is actuated by operation of control valve 42 to actuate caterpillar tracks 8 to drive carriage 2 forwardly, and piston rod 124 is slowly retracted by operation of control valve 140 to lower blade 120 and mole 148, until said mole has entered the ground to the level at which it is desired to lay pipe 144. At the same time, of course, engine 48 is operating through transmission 162 to rotate shaft 90, and

the eccentric pin 88 carried by said shaft is imparting an orbital movement to the forward end of link 84. This orbital movement is transmitted by link 84 and slide 114 to blade 1 20 and mole 148, whereby said mole reproduces to a reduced scale, the orbital movement of pin 88. Thus as the mole enters the ground and reaches its desired depth, it digs a tunnel 182 in the ground, and pulls gripper 160 and pipe 144 into and through said tunnel. The orbital movement of the mole, involving forward and rearward as well as' upward and downward reciprocation, greatly facilitates and enhances the digging action, greatly reducing the power required to perform the operation. Tests have shown that the present machine can be operated with as little as 10 or 15 percent of the power which would be required if the orbital oscillation of the mole were not used. The oscillation also facilitates the forward movement of blade 120 through the soil. The mole operates with the least power when it is free to form tunnel 182 at least partially by upward displacement of the overlying soil, all the way to surface 6. For this reason, the digging face 150 of the mole may be likened to a spade point, having a width equal to the full width of the mole, and facing upwardly, and the rotation of shaft 90 is always clockwise as viewed in FIG. 4, as indicated by arrow 184, so that said mole moves upwardly in the forward portion of its orbit. The upward displacement of the overlying soil may tend to form a raised mole track on the ground surface, and blade 120 of course forms a continuous slit 186 visible at the ground surface. However, the upward displacement of soil is at most very slight, involving no breaking of the soil or damage to sod, and slit 186 may be very narrow, perhaps one-quarter inch or less. Therefore, the soil may be re-compacted and slit 186 closed very simply, as by running one of tracks 8 thereover, leaving no trace at the ground surface that a pipe has been installed therebelow.

The supply of water to the mole by the tube 166, and discharge thereof through bore 162 into tunnel 182, may not be essential in all cases, depending on the nature of the soil, but in many cases has several useful functions. First, it softens the soil in the immediate zone of the mole, easing the digging action of the mole in hard soils. Second, it tends to compact the walls of the tunnel 182, so that there is less tendency for the tunnel to fill immediately with earth behind the mole,

and the pipe can be pulled more easily and with less power. Third, the water lubricates the passage of the pipe through tunnel 182. With the present machine, several hundred feet of pipe have been successfully pulled in very difficult soil.

The orbital motion of mole 148 and the resistance of the soil thereto, of course transmits a reactive force to carriage 2, and if means were not taken to prevent it, the carriage itself would oscillate, particularly vertically, instead of the mole, and the advantages of the orbital digging action would be lost. The required stabilization of the carriage is provided in the present structure by the use of heavy weights 60 to increase the mass of the carriage, and by rendering caterpillar tracks 8 substantially unyieldable by the use of rails 62.

It will be seen also that depending on the nature of the soil, the orbital speed of the mole may desirably require adjustment independently of the carriage speed. That is, hard soils may require very rapid orbiting of the mole at a very slow carriage speed, while soft soils may permit slower orbiting at higher carriage speeds. The control system shown permits this independent adjustment of mole orbiting and carriage speeds.

By inserting bolt 136 of piston rod bracket 122 selectively in any of holes 138 of blade 120, a depth gauge is provided, in that if said bolt is inserted in the proper hole, mole 148 will be disposed at the desired depth in the ground when piston rod 124 is fully retracted. The adjustment of bolt in slots 112 of link 108 adjusts the angle of attack of mole 148, by tilting slide 114 and blade forwardly or rearwardly. In perhaps most cases, and particularly as the mole enters the ground, it is generally preferable that the axis of the mole be inclined slightly downwardly and forwardly. The adjustment of bolt 82 in slots 86 of link 84 adjusts the vertical component of the orbital movement of the mole, since a greater vertical movement may be required to open and maintain tunnel 182 in loose soils. It will be readily apparent that if the lower end of link 74 is adjusted forwardly from the position shown, then the same forward movement of link 84, as produced by eccentric pin 88, will produce a greater vertical movement of the rearward end of link 84, and that this increased vertical movement will in turn be transmitted to the mole.

While we have shown and described a specific embodiment of our invention, it will be readily apparent that many minor changes of structure and operation could be made without departing from the spirit of the invention.

What we claim as new and desire to protect by Letters Patent is:

l. A pipe pulling machine comprising:

a. a carriage supported and powered for movement over the ground surface,

b. a generally vertical blade mounted movably on said carriage, said blade being laterally thinner than the pipe to be pulled,

c. powered means mounted on said carriage for moving said blade vertically relative to said carriage from an elevated position above the ground level to a lowered position in which it projects beneath the ground level and is drawn through the earth by movement of said carriage,

d. an enlarged digging element of greater crosssectional dimensions than the pipe to be pulled affixed to the lower end of said blade and having an upwardly facing digging face at the forward end thereof, with respect to the direction of travel of said carriage,

e. powered means carried by said carriage and operable when actuated to move said blade and digging element in an orbital path lying in a vertical plane aligned with the direction of travel of said carriage, said digging element moving upwardly in the forward portion of its orbit, and

f. means for attaching a pipe to be pulled to the rearward end of said digging element whereby said pipe is pulled into the earth tunnel formed by the forward movement of said digging element, said attaching means being freely flexible so as to be transversely yieldable and freely reducible in effective length, but being rigidly inextensible in length, whereby the forward movement of said pipe is accomplished in a continuous series of short, distinct surges, only the forward component of the orbital movement of the digging element being transmitted to the pipe by said attaching means.

2. A pipe pulling machine as recited in claim 1 with the addition of means operable to vary the vertical component of the orbital movement of said digging element.

3. A pipe pulling machine as recited in claim 1 with the addition of means operable to tilt said blade variably in a vertical plane aligned with the direction of travel of said carriage, whereby to vary the vertical angle of attack of said digging element.

4. A pipe pulling machine as recited in claim 1 wherein said blade is supported on said carriage by means including:

a. a vertical tubular slide in which said blade is longitudinally movable by means of said powered blade elevating means,

b. a first link at its upper end to said carriage on a horizontal transverse axis behind said slide,

c. a second generally horizontal link pivoted at its rearward end to the lower end of said first link, said slide being pivoted adjacent its lower end to said second link on a horizontal transverse axis intemediate the ends of said second link, said powered orbiting means being operable to move the forward end of said second link in an orbital path lying in a vertical plane aligned with the direction of carriage travel, and

d. a third generally horizontal link pivoted at one end to said carriage on a horizontal transverse axis, and pivoted at its opposite end to said slide on a horizontal transverse axis, adjacent the upper end of said slide.

5. A pipe pulling machine as recited in claim 4 with the addition of means operable to adjust the effective length of said second link, whereby to vary the vertical component of the orbital movement of said digging element.

6. A pipe pulling machine as recited in claim 4 with the addition of means operable to vary the effective length of said third link, whereby the vertical angle of attack of said digging element may be varied. 

1. A pipe pulling machine comprising: a. a carriage supported and powered for movement over the ground surface, b. a generally vertical blade mounted movably on said carriage, said blade being laterally thinner than the pipe to be pulled, c. powered means mounted on said carriage for moving said blade vertically relative to said carriage from an elevated position above the ground level to a lowered position in which it projects beneath the ground level and is drawn through the earth by movement of said carriage, d. an enlarged digging element of greater cross-sectional dimensions than the pipe to be pulled affixed to the lower end of said blade and having an upwardly facing digging face at the forward end thereof, with respect to the direction of travel of said carriage, e. powered means carried by said carriage and operable when actuated to move said blade and digging element in an orbital path lying in a vertical plane aligned with the direction of travel of said carriage, said digging element moving upwardly in the forward portion of its orbit, and f. means for attaching a pipe to be pulled to the rearward end of said digging element whereby said pipe is pulled into the earth tunnel formed by the forward movement of said digging element, said attaching means being freely flexible so as to be transversely yieldable and freely reducible in effective length, but being rigidly inextensible in length, whereby the forward movement of said pipe is accomplished in a continuous series of short, distinct surges, only the forward component of the orbital movement of the digging element being transmitted to the pipe by said attaching means.
 2. A pipe pulling machine as recited in claim 1 with the addition of means operable to vary the vertical component of the orbital movement of said digging element.
 3. A pipe pulling machine as recited in claim 1 with the addition of means operable to tilt said blade variably in a vertical plane aligned with the direction of travel of said carriage, whereby to vary the vertical angle of attack of said digging element.
 4. A pipe pulling machine as recited in claim 1 wherein said blade is supported on said carriage by means including: a. a vertical tubular slide in which said blade is longitudinally movable by means of said powered blade elevating means, b. a first link at its upper end to said carriage on a horizontal transverse axis behind said slide, c. a second generally horizontal link pivoted at its rearward end to the lower end of said first link, said slide being pivoted adjacent its lower end to said second link on a horizontal transverse axis intemediate the ends of said second link, said powered orbiting means being operable to move the forward end of said second link in an orbital path lying in a vertical plane aligned with the direction of carriage travel, and d. a third generally horizontal link pivoted at one end to said carriage on a horizontal transverse axis, and pivoted at its opposite end to said slide on a horizontal transverse axis, adjacent the upper end of said slide.
 5. A pipe pulling machine as recited in claim 4 with the addition of means operable to adjust the effective length of said second link, whereby to vary the vertical component of the orbital movement of said digging element.
 6. A pipe pulling machine as recited in claim 4 with the addition of means operable to vary the effective length of said third link, whereby the vertical angle of attack of said digging element may be varied. 